cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-2 of 2 results.

A378494 Intersection of A000379 and A026424.

Original entry on oeis.org

8, 12, 18, 20, 27, 28, 32, 44, 45, 48, 50, 52, 63, 68, 75, 76, 80, 92, 98, 99, 112, 116, 117, 120, 124, 125, 147, 148, 153, 162, 164, 168, 171, 172, 175, 176, 188, 207, 208, 212, 236, 242, 243, 244, 245, 261, 264, 268, 270, 272, 275, 279, 280, 284, 292, 304, 312, 316
Offset: 1

Views

Author

Paolo Xausa, Nov 28 2024, following a suggestion from Peter Munn

Keywords

Comments

First differs from A187042 at n = 24, where a(24) = 120 is missing from A187042.

Crossrefs

Programs

  • Mathematica
    A000379Q[k_] := k == 1 || EvenQ[Count[IntegerDigits[FactorInteger[k][[All, 2]], 2], 1, 2]];
    A026424Q[k_] := OddQ[PrimeOmega[k]];
    Select[Range[500], A000379Q[#] && A026424Q[#] &]

A241270 Numbers with the property that in their factorization over distinct terms of A050376, the sums of prime and nonprime terms of A050376 are equal.

Original entry on oeis.org

126, 468, 624, 792, 880, 1056, 1150, 2900, 3264, 4606, 5824, 6375, 6624, 8320, 9856, 10388, 11375, 12798, 13650, 16400, 16704, 19250, 20925, 30135, 32625, 36720, 39150, 39900, 53784, 56446, 56925, 57000, 59500, 63455, 65520, 71400, 71500, 72471
Offset: 1

Views

Author

Vladimir Shevelev, Apr 18 2014

Keywords

Comments

The corresponding sequence of the sum over the primes, which equals the sum over the nonprimes, is 9, 13, 16, 13, 16, 16, 25, 29, 20, 49, 20, 25, 25, 20, 20, 53, 25, 81, 25, 41, 29, 25, 34, 49, 34, 25, 34, 29, 85, 169, 34, 29, 29, 49, 25, 29, 29, 49, ... - Wolfdieter Lang, Apr 25 2014

Examples

			126 and 468 are in the sequence since the factorizations are 2*7*9 and 4*9*13 respectively, and 2+7=9, 4+9=13.
		

References

  • V. S. Shevelev, Multiplicative functions in the Fermi-Dirac arithmetic, Izvestia Vuzov of the North-Caucasus region, Nature sciences 4 (1996), 28-43 [Russian].

Crossrefs

Extensions

More terms from Peter J. C. Moses, Apr 18 2014
New extension from Wolfdieter Lang, Apr 25 2014
Showing 1-2 of 2 results.